Rotary fan impeller



Sept. 28, 1954 R, C, DAvls 2,690,063

l' ROTARY FAN IMPELLER Filed March 5, 1951 Patented Sept. 28, 1954 NT OFFICE l ROTARY FAN IMPELLER Raymond C. Davis, Dayton, Ohio, assigner to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application March 3, 1951, Serial No. 213,768

Z'Claims.

1 This invention relates to the construction of rotary fans, especially such as electric fans commonly used for circulating air in homes and omces.

An object of the invention is to provide a simple and efficient structure of the fan rotor which will materially cushion the vibrations of the fan impeller blades and also prevent transmission of noise or other vibrations between the fan blades and the driving shaft of the fan.

A more specific object is to provide a fan blade unit resiliently mounted upon a central hub structure by a metal isolating strip of cushioning yieldable rubber` (or other rubber-like non-metallic material) in such manner that the fan blade unit may be quickly and readily attached and detached from its central hub structure at any time.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is an end View of a fan rotor made according to this invention, parts of the impeller blades being broken away.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

Reference numeral I designates the impeller hub which is suitably fixed to the drive shaft II of the electric motor I2. A sheet metal hub plate I3 is rigidly fixed to hub I0 by any suitable means, preferably by welding.

A fan impeller unit I5 comprises fan blades I6 integral with or suitably fixed to a central radially disposed plate I1. In the form illustrated the central structure of the impeller unit is a dished metal annular plate I1 having a series of fan blades I6 riveted thereto. The blades I6 of course are given the desired pitch to cause an axial fiow of the air in a manner Well known. The inner peripheral portion of plate I'I extends radially inwardly in substantially the same radial plane as the radially outwardly extending peripheral portion 2I of the hub plate I3 and is radially spaced therefrom a suitably short distance 22 of around say onequarter to three-eighths of an inch. These peripheral portions 20 and 2I are imbedded in and yieldably connected together by an interposed strip 25 of soft rubber or other well-known rubber-like material.

Preferably strip 25, is made in long or continuous lengths of the desired uniform cross section by the well-known extrusion method of making such strips in a very economical way. Strip 25, when shaped by the extrusion die, has formed therein the opposed grooves 26 and 21 to receive the marginal portions 20 and 2I respectively. Strip 25 also has a third or spreader groove 28 formed therein which is adapted to receive a separately made wedging spreader strip 30 at the time strip 25 is assembled in place to securely connect plate I1 to hub plate I3.

The assembling of the impeller unit I5 to the hub plate I3 will now be described. First a sufficient length of the flexible rubber strip 25 is cut olf from the much longer length in which it is originally made, and this shorter length of strip 25 is iiexed and extended around the inner periphery of plate I'I so that the marginal portion 20 thereof is inserted within groove 2'I in said strip 25 and so the two ends of strip 25 meet at a suitable butt joint 29. Then impeller unit I5 with strip 25 attached thereto is moved into position adjacent hub plate I3. By distorting the flexible rubber material of strip 25 (that is by bending the inside wing adjacent groove 26 into the then unfilled groove 30 of said strip) the strip 25 may be snapped into place so that the marginal portion 2| is received within its groove 26. Then the separate wedging strip 30 is forced into its groove 28 progressively all around the now ring-shaped strip 25 and is retained in place within groove 28 by opposed overhanging lips thereon as shown in Fig. 2. This wedging strip 30 is made with such cross section that when forced to its final position (as shown) it will compress the material of strip 25 into tight engagement with the marginal portions 20 and 2 I, that is, the grooves 26 and 2l will be closed tightly upon the portions 20 and 2| inserted therein. Thus the impeller unit I5 is drivingly secured to the hub plate I3 by a resilient cush-v ioning connection which will substantially prevent transmission of sound and other vibrations therebetween and so materially reduces noise from operation of the fan.

Of course many variations may be made in the design of the impeller unit I5 without affecting the essential structure of this invention, which is the simple and economical sounddeadening cushioning strip 25 interposed between the impeller unit and its driven control hub.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

l. A fan rotor comprising: a metal hub adapted to be Xed to a power-driven shaft and having an outwardly projecting hub iiange, an impeller unit having an inwardly projecting metal ange whose inner periphery is flexibly attached to the outer periphery of said hub flange by a strip of cushioning flexible non-metallic material interposed between said flanges, said strip having two opposed grooves therein receiving the adjacent margins respectively of said two flanges, said strip having a filler groove and a wedging filler strip forcibly inserted into said ller groove to thereby compress said two flange-receiving grooves into tight frictional engagement with the meta-1 flanges inserted therein.

2. A fan rotor comprising a metal hub having a radially outwardly projecting metal ange, an impeller unit having a radially inwardly projecting metal ange whose inner peripheral edge lies spaced from but substantially radially aligned with the outer peripheral edge o said hub flange, and an elongated strip of cushioning resilient non-metallic material extending lengthwise around and yieldably connecting said inner and outer peripheral edges, said strip having two opposed continuous grooves therein receiving the adjacent marginall portions of said lflanges, and wedging means embedded in said strip for maintaining the resilient material of said strip distorted and compressed into tight driving engagement with said marginal portions.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,097,318 Dowell Oct. 26, 193'? 2,312,822 Julien et al. Mar. 2, 1943 2,354,101 Broders July 18, 1944 

